1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* incoming call handling 3 * 4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. 5 * Written by David Howells (dhowells@redhat.com) 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 10 #include <linux/module.h> 11 #include <linux/net.h> 12 #include <linux/skbuff.h> 13 #include <linux/errqueue.h> 14 #include <linux/udp.h> 15 #include <linux/in.h> 16 #include <linux/in6.h> 17 #include <linux/icmp.h> 18 #include <linux/gfp.h> 19 #include <linux/circ_buf.h> 20 #include <net/sock.h> 21 #include <net/af_rxrpc.h> 22 #include <net/ip.h> 23 #include "ar-internal.h" 24 25 static void rxrpc_dummy_notify(struct sock *sk, struct rxrpc_call *call, 26 unsigned long user_call_ID) 27 { 28 } 29 30 /* 31 * Preallocate a single service call, connection and peer and, if possible, 32 * give them a user ID and attach the user's side of the ID to them. 33 */ 34 static int rxrpc_service_prealloc_one(struct rxrpc_sock *rx, 35 struct rxrpc_backlog *b, 36 rxrpc_notify_rx_t notify_rx, 37 unsigned long user_call_ID, gfp_t gfp, 38 unsigned int debug_id) 39 { 40 struct rxrpc_call *call, *xcall; 41 struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk)); 42 struct rb_node *parent, **pp; 43 int max, tmp; 44 unsigned int size = RXRPC_BACKLOG_MAX; 45 unsigned int head, tail, call_head, call_tail; 46 47 max = rx->sk.sk_max_ack_backlog; 48 tmp = rx->sk.sk_ack_backlog; 49 if (tmp >= max) { 50 _leave(" = -ENOBUFS [full %u]", max); 51 return -ENOBUFS; 52 } 53 max -= tmp; 54 55 /* We don't need more conns and peers than we have calls, but on the 56 * other hand, we shouldn't ever use more peers than conns or conns 57 * than calls. 58 */ 59 call_head = b->call_backlog_head; 60 call_tail = READ_ONCE(b->call_backlog_tail); 61 tmp = CIRC_CNT(call_head, call_tail, size); 62 if (tmp >= max) { 63 _leave(" = -ENOBUFS [enough %u]", tmp); 64 return -ENOBUFS; 65 } 66 max = tmp + 1; 67 68 head = b->peer_backlog_head; 69 tail = READ_ONCE(b->peer_backlog_tail); 70 if (CIRC_CNT(head, tail, size) < max) { 71 struct rxrpc_peer *peer; 72 73 peer = rxrpc_alloc_peer(rx->local, gfp, rxrpc_peer_new_prealloc); 74 if (!peer) 75 return -ENOMEM; 76 b->peer_backlog[head] = peer; 77 smp_store_release(&b->peer_backlog_head, 78 (head + 1) & (size - 1)); 79 } 80 81 head = b->conn_backlog_head; 82 tail = READ_ONCE(b->conn_backlog_tail); 83 if (CIRC_CNT(head, tail, size) < max) { 84 struct rxrpc_connection *conn; 85 86 conn = rxrpc_prealloc_service_connection(rxnet, gfp); 87 if (!conn) 88 return -ENOMEM; 89 b->conn_backlog[head] = conn; 90 smp_store_release(&b->conn_backlog_head, 91 (head + 1) & (size - 1)); 92 } 93 94 /* Now it gets complicated, because calls get registered with the 95 * socket here, with a user ID preassigned by the user. 96 */ 97 call = rxrpc_alloc_call(rx, gfp, debug_id); 98 if (!call) 99 return -ENOMEM; 100 call->flags |= (1 << RXRPC_CALL_IS_SERVICE); 101 rxrpc_set_call_state(call, RXRPC_CALL_SERVER_PREALLOC); 102 __set_bit(RXRPC_CALL_EV_INITIAL_PING, &call->events); 103 104 trace_rxrpc_call(call->debug_id, refcount_read(&call->ref), 105 user_call_ID, rxrpc_call_new_prealloc_service); 106 107 write_lock(&rx->call_lock); 108 109 /* Check the user ID isn't already in use */ 110 pp = &rx->calls.rb_node; 111 parent = NULL; 112 while (*pp) { 113 parent = *pp; 114 xcall = rb_entry(parent, struct rxrpc_call, sock_node); 115 if (user_call_ID < xcall->user_call_ID) 116 pp = &(*pp)->rb_left; 117 else if (user_call_ID > xcall->user_call_ID) 118 pp = &(*pp)->rb_right; 119 else 120 goto id_in_use; 121 } 122 123 call->user_call_ID = user_call_ID; 124 call->notify_rx = notify_rx; 125 if (rx->app_ops && 126 rx->app_ops->user_attach_call) { 127 rxrpc_get_call(call, rxrpc_call_get_kernel_service); 128 rx->app_ops->user_attach_call(call, user_call_ID); 129 } 130 131 rxrpc_get_call(call, rxrpc_call_get_userid); 132 rb_link_node(&call->sock_node, parent, pp); 133 rb_insert_color(&call->sock_node, &rx->calls); 134 set_bit(RXRPC_CALL_HAS_USERID, &call->flags); 135 136 list_add(&call->sock_link, &rx->sock_calls); 137 138 write_unlock(&rx->call_lock); 139 140 rxnet = call->rxnet; 141 spin_lock(&rxnet->call_lock); 142 list_add_tail_rcu(&call->link, &rxnet->calls); 143 spin_unlock(&rxnet->call_lock); 144 145 b->call_backlog[call_head] = call; 146 smp_store_release(&b->call_backlog_head, (call_head + 1) & (size - 1)); 147 _leave(" = 0 [%d -> %lx]", call->debug_id, user_call_ID); 148 return 0; 149 150 id_in_use: 151 write_unlock(&rx->call_lock); 152 rxrpc_cleanup_call(call); 153 _leave(" = -EBADSLT"); 154 return -EBADSLT; 155 } 156 157 /* 158 * Allocate the preallocation buffers for incoming service calls. These must 159 * be charged manually. 160 */ 161 int rxrpc_service_prealloc(struct rxrpc_sock *rx, gfp_t gfp) 162 { 163 struct rxrpc_backlog *b = rx->backlog; 164 165 if (!b) { 166 b = kzalloc(sizeof(struct rxrpc_backlog), gfp); 167 if (!b) 168 return -ENOMEM; 169 rx->backlog = b; 170 } 171 172 return 0; 173 } 174 175 /* 176 * Discard the preallocation on a service. 177 */ 178 void rxrpc_discard_prealloc(struct rxrpc_sock *rx) 179 { 180 struct rxrpc_backlog *b = rx->backlog; 181 struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk)); 182 unsigned int size = RXRPC_BACKLOG_MAX, head, tail; 183 184 if (!b) 185 return; 186 rx->backlog = NULL; 187 188 /* Make sure that there aren't any incoming calls in progress before we 189 * clear the preallocation buffers. 190 */ 191 spin_lock_irq(&rx->incoming_lock); 192 spin_unlock_irq(&rx->incoming_lock); 193 194 head = b->peer_backlog_head; 195 tail = b->peer_backlog_tail; 196 while (CIRC_CNT(head, tail, size) > 0) { 197 struct rxrpc_peer *peer = b->peer_backlog[tail]; 198 rxrpc_put_local(peer->local, rxrpc_local_put_prealloc_peer); 199 kfree(peer); 200 tail = (tail + 1) & (size - 1); 201 } 202 203 head = b->conn_backlog_head; 204 tail = b->conn_backlog_tail; 205 while (CIRC_CNT(head, tail, size) > 0) { 206 struct rxrpc_connection *conn = b->conn_backlog[tail]; 207 write_lock(&rxnet->conn_lock); 208 list_del(&conn->link); 209 list_del(&conn->proc_link); 210 write_unlock(&rxnet->conn_lock); 211 kfree(conn); 212 if (atomic_dec_and_test(&rxnet->nr_conns)) 213 wake_up_var(&rxnet->nr_conns); 214 tail = (tail + 1) & (size - 1); 215 } 216 217 head = b->call_backlog_head; 218 tail = b->call_backlog_tail; 219 while (CIRC_CNT(head, tail, size) > 0) { 220 struct rxrpc_call *call = b->call_backlog[tail]; 221 rcu_assign_pointer(call->socket, rx); 222 if (rx->app_ops && 223 rx->app_ops->discard_new_call) { 224 _debug("discard %lx", call->user_call_ID); 225 rx->app_ops->discard_new_call(call, call->user_call_ID); 226 if (call->notify_rx) 227 call->notify_rx = rxrpc_dummy_notify; 228 rxrpc_put_call(call, rxrpc_call_put_kernel); 229 } 230 rxrpc_call_completed(call); 231 rxrpc_release_call(rx, call); 232 rxrpc_put_call(call, rxrpc_call_put_discard_prealloc); 233 tail = (tail + 1) & (size - 1); 234 } 235 236 kfree(b); 237 } 238 239 /* 240 * Allocate a new incoming call from the prealloc pool, along with a connection 241 * and a peer as necessary. 242 */ 243 static struct rxrpc_call *rxrpc_alloc_incoming_call(struct rxrpc_sock *rx, 244 struct rxrpc_local *local, 245 struct rxrpc_peer *peer, 246 struct rxrpc_connection *conn, 247 const struct rxrpc_security *sec, 248 struct sockaddr_rxrpc *peer_srx, 249 struct sk_buff *skb) 250 { 251 struct rxrpc_backlog *b = rx->backlog; 252 struct rxrpc_call *call; 253 unsigned short call_head, conn_head, peer_head; 254 unsigned short call_tail, conn_tail, peer_tail; 255 unsigned short call_count, conn_count; 256 257 /* #calls >= #conns >= #peers must hold true. */ 258 call_head = smp_load_acquire(&b->call_backlog_head); 259 call_tail = b->call_backlog_tail; 260 call_count = CIRC_CNT(call_head, call_tail, RXRPC_BACKLOG_MAX); 261 conn_head = smp_load_acquire(&b->conn_backlog_head); 262 conn_tail = b->conn_backlog_tail; 263 conn_count = CIRC_CNT(conn_head, conn_tail, RXRPC_BACKLOG_MAX); 264 ASSERTCMP(conn_count, >=, call_count); 265 peer_head = smp_load_acquire(&b->peer_backlog_head); 266 peer_tail = b->peer_backlog_tail; 267 ASSERTCMP(CIRC_CNT(peer_head, peer_tail, RXRPC_BACKLOG_MAX), >=, 268 conn_count); 269 270 if (call_count == 0) 271 return NULL; 272 273 if (!conn) { 274 if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_service_conn)) 275 peer = NULL; 276 if (!peer) { 277 peer = b->peer_backlog[peer_tail]; 278 peer->srx = *peer_srx; 279 b->peer_backlog[peer_tail] = NULL; 280 smp_store_release(&b->peer_backlog_tail, 281 (peer_tail + 1) & 282 (RXRPC_BACKLOG_MAX - 1)); 283 284 rxrpc_new_incoming_peer(local, peer); 285 } 286 287 /* Now allocate and set up the connection */ 288 conn = b->conn_backlog[conn_tail]; 289 b->conn_backlog[conn_tail] = NULL; 290 smp_store_release(&b->conn_backlog_tail, 291 (conn_tail + 1) & (RXRPC_BACKLOG_MAX - 1)); 292 conn->local = rxrpc_get_local(local, rxrpc_local_get_prealloc_conn); 293 conn->peer = peer; 294 rxrpc_see_connection(conn, rxrpc_conn_see_new_service_conn); 295 rxrpc_new_incoming_connection(rx, conn, sec, skb); 296 } else { 297 rxrpc_get_connection(conn, rxrpc_conn_get_service_conn); 298 atomic_inc(&conn->active); 299 } 300 301 /* And now we can allocate and set up a new call */ 302 call = b->call_backlog[call_tail]; 303 b->call_backlog[call_tail] = NULL; 304 smp_store_release(&b->call_backlog_tail, 305 (call_tail + 1) & (RXRPC_BACKLOG_MAX - 1)); 306 307 rxrpc_see_call(call, rxrpc_call_see_accept); 308 call->local = rxrpc_get_local(conn->local, rxrpc_local_get_call); 309 call->conn = conn; 310 call->security = conn->security; 311 call->security_ix = conn->security_ix; 312 call->peer = rxrpc_get_peer(conn->peer, rxrpc_peer_get_accept); 313 call->dest_srx = peer->srx; 314 call->cong_ssthresh = call->peer->cong_ssthresh; 315 call->tx_last_sent = ktime_get_real(); 316 return call; 317 } 318 319 /* 320 * Set up a new incoming call. Called from the I/O thread. 321 * 322 * If this is for a kernel service, when we allocate the call, it will have 323 * three refs on it: (1) the kernel service, (2) the user_call_ID tree, (3) the 324 * retainer ref obtained from the backlog buffer. Prealloc calls for userspace 325 * services only have the ref from the backlog buffer. 326 * 327 * If we want to report an error, we mark the skb with the packet type and 328 * abort code and return false. 329 */ 330 bool rxrpc_new_incoming_call(struct rxrpc_local *local, 331 struct rxrpc_peer *peer, 332 struct rxrpc_connection *conn, 333 struct sockaddr_rxrpc *peer_srx, 334 struct sk_buff *skb) 335 { 336 const struct rxrpc_security *sec = NULL; 337 struct rxrpc_skb_priv *sp = rxrpc_skb(skb); 338 struct rxrpc_call *call = NULL; 339 struct rxrpc_sock *rx; 340 341 _enter(""); 342 343 /* Don't set up a call for anything other than a DATA packet. */ 344 if (sp->hdr.type != RXRPC_PACKET_TYPE_DATA) 345 return rxrpc_protocol_error(skb, rxrpc_eproto_no_service_call); 346 347 read_lock_irq(&local->services_lock); 348 349 /* Weed out packets to services we're not offering. Packets that would 350 * begin a call are explicitly rejected and the rest are just 351 * discarded. 352 */ 353 rx = local->service; 354 if (!rx || (sp->hdr.serviceId != rx->srx.srx_service && 355 sp->hdr.serviceId != rx->second_service) 356 ) { 357 if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA && 358 sp->hdr.seq == 1) 359 goto unsupported_service; 360 goto discard; 361 } 362 363 if (!conn) { 364 sec = rxrpc_get_incoming_security(rx, skb); 365 if (!sec) 366 goto unsupported_security; 367 } 368 369 spin_lock(&rx->incoming_lock); 370 if (rx->sk.sk_state == RXRPC_SERVER_LISTEN_DISABLED || 371 rx->sk.sk_state == RXRPC_CLOSE) { 372 rxrpc_direct_abort(skb, rxrpc_abort_shut_down, 373 RX_INVALID_OPERATION, -ESHUTDOWN); 374 goto no_call; 375 } 376 377 call = rxrpc_alloc_incoming_call(rx, local, peer, conn, sec, peer_srx, 378 skb); 379 if (!call) { 380 skb->mark = RXRPC_SKB_MARK_REJECT_BUSY; 381 goto no_call; 382 } 383 384 trace_rxrpc_receive(call, rxrpc_receive_incoming, 385 sp->hdr.serial, sp->hdr.seq); 386 387 /* Make the call live. */ 388 rxrpc_incoming_call(rx, call, skb); 389 conn = call->conn; 390 391 if (rx->app_ops && 392 rx->app_ops->notify_new_call) 393 rx->app_ops->notify_new_call(&rx->sk, call, call->user_call_ID); 394 395 spin_lock(&conn->state_lock); 396 if (conn->state == RXRPC_CONN_SERVICE_UNSECURED) { 397 conn->state = RXRPC_CONN_SERVICE_CHALLENGING; 398 set_bit(RXRPC_CONN_EV_CHALLENGE, &call->conn->events); 399 rxrpc_queue_conn(call->conn, rxrpc_conn_queue_challenge); 400 } 401 spin_unlock(&conn->state_lock); 402 403 spin_unlock(&rx->incoming_lock); 404 read_unlock_irq(&local->services_lock); 405 406 if (hlist_unhashed(&call->error_link)) { 407 spin_lock_irq(&call->peer->lock); 408 hlist_add_head(&call->error_link, &call->peer->error_targets); 409 spin_unlock_irq(&call->peer->lock); 410 } 411 412 _leave(" = %p{%d}", call, call->debug_id); 413 rxrpc_queue_rx_call_packet(call, skb); 414 rxrpc_put_call(call, rxrpc_call_put_input); 415 return true; 416 417 unsupported_service: 418 read_unlock_irq(&local->services_lock); 419 return rxrpc_direct_abort(skb, rxrpc_abort_service_not_offered, 420 RX_INVALID_OPERATION, -EOPNOTSUPP); 421 unsupported_security: 422 read_unlock_irq(&local->services_lock); 423 return rxrpc_direct_abort(skb, rxrpc_abort_service_not_offered, 424 RX_INVALID_OPERATION, -EKEYREJECTED); 425 no_call: 426 spin_unlock(&rx->incoming_lock); 427 read_unlock_irq(&local->services_lock); 428 _leave(" = f [%u]", skb->mark); 429 return false; 430 discard: 431 read_unlock_irq(&local->services_lock); 432 return true; 433 } 434 435 /* 436 * Charge up socket with preallocated calls, attaching user call IDs. 437 */ 438 int rxrpc_user_charge_accept(struct rxrpc_sock *rx, unsigned long user_call_ID) 439 { 440 struct rxrpc_backlog *b = rx->backlog; 441 442 if (rx->sk.sk_state == RXRPC_CLOSE) 443 return -ESHUTDOWN; 444 445 return rxrpc_service_prealloc_one(rx, b, NULL, user_call_ID, GFP_KERNEL, 446 atomic_inc_return(&rxrpc_debug_id)); 447 } 448 449 /* 450 * rxrpc_kernel_charge_accept - Charge up socket with preallocated calls 451 * @sock: The socket on which to preallocate 452 * @notify_rx: Event notification function for the call 453 * @user_call_ID: The tag to attach to the preallocated call 454 * @gfp: The allocation conditions. 455 * @debug_id: The tracing debug ID. 456 * 457 * Charge up the socket with preallocated calls, each with a user ID. The 458 * ->user_attach_call() callback function should be provided to effect the 459 * attachment from the user's side. The user is given a ref to hold on the 460 * call. 461 * 462 * Note that the call may be come connected before this function returns. 463 */ 464 int rxrpc_kernel_charge_accept(struct socket *sock, rxrpc_notify_rx_t notify_rx, 465 unsigned long user_call_ID, gfp_t gfp, 466 unsigned int debug_id) 467 { 468 struct rxrpc_sock *rx = rxrpc_sk(sock->sk); 469 struct rxrpc_backlog *b = rx->backlog; 470 471 if (sock->sk->sk_state == RXRPC_CLOSE) 472 return -ESHUTDOWN; 473 474 return rxrpc_service_prealloc_one(rx, b, notify_rx, user_call_ID, 475 gfp, debug_id); 476 } 477 EXPORT_SYMBOL(rxrpc_kernel_charge_accept); 478